A basic (hopefully) conditional probability question, but I can't get my head around.

I want to calculate the probability based on past data that a team will score a goal, say in soccer (football to the Europeans, of which I am one ). I imagine this depends not only on Team A's scoring record, but also Team B's likelihood to concede.

So:

Say Team A, in their last 100 games has scored 1 goal 50 times and 0 goals 50 times. Therefore there is a probability of 0.5 that they will score a goal.

However, Team B, in their last 100 games have conceded a goal in only 25 of their games and conceded no goals in 75. I.e. probability to concede a goal is 0.25.

For Team A to score a goal, it has to score one, but Team B must concede one. So is this a simple multiplication of the probabilities, 0.5*0.25?

However there is clearly some correlation between the two events, which leads me to think it's not as straightforward as this. Can someone comment on what the probability would be?

Thanks

Regards

neorich